Epi (version 2.0)

diet: Diet and heart data

Description

The diet data frame has 337 rows and 14 columns. The data concern a subsample of subjects drawn from larger cohort studies of the incidence of coronary heart disease (CHD). These subjects had all completed a 7-day weighed dietary survey while taking part in validation studies of dietary questionnaire methods. Upon the closure of the MRC Social Medicine Unit, from where these studies were directed, it was found that 46 CHD events had occurred in this group, thus allowing a serendipitous study of the relationship between diet and the incidence of CHD.

Format

This data frame contains the following columns:

id:

subject identifier, a numeric vector.

doe:

date of entry into follow-up study, a Date variable.

dox:

date of exit from the follow-up study, a Date variable.

dob:

date of birth, a Date variable.

y:

- number of years at risk, a numeric vector.

fail:

status on exit, a numeric vector (codes 1, 3, 11, and 13 represent CHD events)

job:

occupation, a factor with levels Driver Conductor Bank worker

month:

month of dietary survey, a numeric vector

energy:

total energy intake (KCal per day/100), a numeric vector

height:

(cm), a numeric vector

weight:

(kg), a numeric vector

fat:

fat intake (g/day), a numeric vector

fibre:

dietary fibre intake (g/day), a numeric vector

energy.grp:

high daily energy intake, a factor with levels <=2750 kcal<="" code=""> >2750 KCal

chd:

CHD event, a numeric vector (1=CHD event, 0=no event)

Source

The data are described and used extensively by Clayton and Hills, Statistical Models in Epidemiology, Oxford University Press, Oxford:1993. They were rescued from destruction by David Clayton and reentered from paper printouts.

Examples

data(diet)
# Illustrate the follow-up in a Lexis diagram
Lexis.diagram( age=c(30,75), date=c(1965,1990),
               entry.date=cal.yr(doe), exit.date=cal.yr(dox), birth.date=cal.yr(dob), 
               fail=(fail>0), pch.fail=c(NA,16), col.fail=c(NA,"red"), cex.fail=1.0,
               data=diet )